Oct 18 2007

Hypnotic Trance or Mass Delusion

Students at Logan High School were recently treated to a fund raising event that features a stage hypnotist. This seemingly benign event resulted in one student ending up in the hospital and many others frightened, leading the school to ban further such events. One student described the event thusly:

“I couldn’t really tell what was going on because people were just crying and it seemed like they were totally normal and awake but I guess they were in a trance or something, it was weird.”

The hypnotist was as surprised as anyone by these events, claiming that he had never experienced such a reaction before. What really happened here?

Hypnotism is a strange phenomenon and it is difficult to tell exactly what is going on because it is not possible to read someone’s mind. Is the subject actually in a “trance” – meaning an altered state of awareness, or are they just roleplaying being in a trance. Nothing actually happens during a hypnotism that is incompatible with the subject simply acting, but that does not mean that acting is necessarily all that is going on.

Hypnosis may be simple guided daydreaming, where subjects are encouraged to imagine themselves in a past life or being abducted by aliens. Perhaps in some cases the hypnotic state (if one even exists) is merely heightened suggestibility. Stage hypnotists typically will use procedures for screening the audience for those who are suggestible. So they are not so much putting people into a suggestible state by finding subjects who are already suggestible.

There is also a social context to hypnotism. The hypnotists and the context of the stage performance gives subjects permission to loosen their inhibitions. It also may create social pressure to conform to the expectations of the performance. This pressure would not work on everyone, but then again the stage magician can screen for those on whom they will work.

Recent technology, specifically functional MRI scanning, has given us the ability to peak inside the brain (not quite mind reading, but a good substitute). We are now starting to see studies where fMRI was used to image brain function during hypnosis. In this study, for example, brain activity during pain stimulus was looked at with and without hypnosis and what is called “analgesic suggestion.” Those subjects (this was a very small study, so the results should be considered preliminary) who were given a suggestion of pain relief experienced less pain and those parts of their brains that typically react to pain demonstrated less activity. This does not indicate that subjects were anyway in an altered state, and can simply mean that the expectation of pain or analgesia affected their subjective experience of pain, and of course was reflected in the corresponding brain activity.

The question remains – what, exactly, is hypnosis? I am unconvinced that it represents an “altered state” by which I mean that brain activity is altered in such a way that the construct of consciousness is different. It therefore does not deserve the designation of “trance,” which definitely implies a state that can be distinguished from wakefulness.

However it probably represents, at least in some cases, varying attention and alertness. In this study, for example, it was found that those under hypnosis (a suggestive term that is probably misleading) could not be distinguished from those in a relaxed but fully conscious state. Also, this PET scan study found that cortical activity during hypnosis was similar to simple relaxation.

The study also looked at pain perception and found sensory cortex activation differences. It seems that our brains are hardwired in such a way that we can psychologically increase or decrease our perception of pain, making pain amenable to cognitive or hypnotic intervention. We can speculate about the evolutionary advantage such hardwiring would provide. This also explains why pain is so susceptible to placebo effects.

In light of all this, what happened at Logan High School? I don’t think the stage magician actually placed any students in a trance or altered state. The students were responding to suggestion and expectation – and were mostly just having fun. All it takes is one particularly suggestible and/or anxious student, however, to set off a chain reaction. The combination of the hypnotic suggestion with a fearful response was enough to spark a mass delusion, where many students believed “something weird” was happening.

Separating out psychological and neurological causes of hypnosis and similar phenomena is challenging, but neuroscience research is beginning to tackle these questions. I expect that fMRI and newer techniques still to come will provide researchers with the tools to more definitely answer these interesting questions. But I think we have enough evidence at this time to conclude that hypnosis is not a true altered state or trance but rather is an interaction with the conscious state, involving mostly suggestibility and guided imagination.

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